The burden of human immunodeficiency virus (HIV) on different racial/ethnic groups remains one of the most extreme examples of a racial disparity in health among Americans. HIV infection is significantly higher among non-Hispanic blacks than among any other racial/ethnic group in the United States. There is now evidence that sexual network dynamics, including overlapping sexual partnerships (concurrency) play an important role in racial disparities in HIV. Due to structural factors, including highly disproportionate incarceration rates, African- Americans are more likely to be in sexual networks where people have more concurrent sexual partners. Mathematical models show that achieving very small reductions in levels of sexual concurrency can have a dramatic impact on the chain of HIV transmission. Our Community Action Board (CAB) of the Center for AIDS &STD Working Group on Disparities has prioritized developing health communication messages about sexual networks to help reduce HIV stigma and transmission in communities of African heritage. In this research, we will utilize community-based participatory research methods to translate the science of sexual networks into culturally-resonant HIV prevention messages as a new approach to help reduce racial disparities in HIV. Aim 1: Undertake formative research to develop HIV prevention messages that convey the importance of sexual network dynamics in King County, Washington. The CAB Disparities Working Group will conduct focus groups and interviews with a) native-born African-Americans and b) foreign-born blacks (Ethiopian and Kenyan immigrants, who are the majority of incident HIV among foreign-born blacks in King County). We will develop a multimedia tool in English, Kiswahili, and Amharic illustrating principles of HIV transmission in sexual networks for use in community discussions. We will identify sexual network message dissemination channels in the target populations including social network approaches (person-to-person communication), civil society approaches (faith-based organizations, community events and organizations), and the media. Subaim 2.1.1. We will continue to inform ourselves about best practices in community-participatory research via seminars and discussions. Aim 2: Pilot and evaluate the impact of the HIV prevention concurrency messages among populations of African-Americans and African-born populations in King County. The CAB Disparities Working Group will launch HIV prevention concurrency messaging and evaluate acceptability and impact, including message comprehension and recall (1-month post recall among n=30 African-Americans and n=30 Kenyans and Ethiopians), intention, and attitude strength. The CAB Working Group will develop and implement a manual of community-based research translation processes used including community outreach, HIV prevention message development, and message dissemination in affected communities. Subaim 2.2.1. We will build capacity by educating ourselves about cutting edge approaches to development and marketing of health messages. Aim 3: HIV disparity message findings and tools will be shared in a national seminar. We will invite the national Center for AIDS Research network and their CABs to a national meeting, where we will also explore the feasibility of a community-collaborative multi-site randomized controlled trial assessing impact of a sexual concurrency intervention for HIV prevention in areas with large populations of African- Americans and African immigrants. PUBLIC HEALTH RELEVANCE: This study addresses the critical and persistent disparity in HIV among persons of African heritage. A novel sexual network approach that translates new scientific understanding into culturally-resonant prevention messages delivered within a community-participatory framework has the potential to be implemented for other similar populations across the US.